This disclosure refers to both particles and powders. These two terms are equivalent, except for the caveat that a singular “powder” refers to a collection of particles. The present invention may apply to a wide variety of powders and particles. Powders that fall within the scope of the present invention may include, but are not limited to, any of the following: (a) nano-structured powders(nano-powders), having an average grain size less than 250 nanometers and an aspect ratio between one and one million; (b) submicron powders, having an average grain size less than 1 micron and an aspect ratio between one and one million; (c) ultra-fine powders, having an average grain size less than 100 microns and an aspect ratio between one and one million; and (d) fine powders, having an average grain size less than 500 microns and an aspect ratio between one and one million.
Powders may be used in a wide variety of applications. In preparation for their respective applications, powders can be operated on by a plasma arc chamber. In one embodiment, the plasma arc chamber comprises two spaced apart electrodes. Working gas flows through the chamber. When current is passed across the gap between the two electrodes, the current energizes the working gas and forms a plasma arc.
FIGS. 1-2 illustrate one embodiment of a general work flow 100 and a simplified system 200 for operating on a powder using a plasma arc chamber. System 200 is presented for illustrative purposes only and is not intended to limit the present invention with respect to size and shape beyond the scope of the claims. Powder is provided by a powder supply 204. For example, the powder can be provided by a cannister of powder. At step 104, the powder is fluidized, such as by means of an introduction gas. At step 106, the fluidized powder then flows through a conduit 206, such as a hose, and into the plasma arc chamber 208. At step 108, the powder is operated on by the plasma arc chamber. Such operation preferably includes a plasma arc being generated by the plasma arc chamber and vaporizing the powder. This vaporization can be used for a variety of different applications, including, but not limited to, nano-sizing the powder, coating the powder, and applying the powder as a coating.
However, problems can arise in flowing the powder through the conduit into the plasma arc chamber. Inter-particle forces between the particles can cause attraction and agglomeration of the particles, making the powder difficult to flow and leading to an inconsistent feed. As a result, the powder is not provided with sufficient control and uniformity.
What is needed in the art is a process for modulating the inter-particle forces between the powder particles in order to enhance the powder's flowability.